Computer-assisted, Le Fort-based, face–jaw–teeth transplantation: a pilot study on system feasiblity and translational assessment

Abstract

Purpose Le Fort-based face–jaw–teeth transplantation (FJTT) attempts to marry bone and teeth geometry of size-mismatched face–jaw–teeth segments to restore function and form due to severe mid-facial trauma. Recent development of a computer-assisted planning and execution (CAPE) system for Le Fort-based FJTT in a pre-clinical swine model offers preoperative planning, and intraoperative navigation. This paper addresses the translation of the CAPE system to human anatomy and presents accuracy results. Methods Single-jaw, Le Fort-based FJTTs were performed on plastic models, one swine and one human, and on a human cadaver. Preoperative planning defined the goal placement of the donor’s Le Fort-based FJTT segment on the recipient. Patient-specific navigated cutting guides helped achieve planned osteotomies. Intraoperative cutting guide and donor fragment placement were compared with postoperative computed tomography (CT) data and the preoperative plan. Results Intraoperative measurement error with respect to postoperative CT was less than 1.25 mm for both mock transplants and 3.59 mm for the human cadaver scenario. Donor fragment placement (as compared to the planned position) was less accurate for the human model test case (2.91 mm) compared with the swine test (2.25 mm) and human cadaver (2.26 mm). Conclusion The results indicate the viability of the CAPE system for assisting with Le Fort-based FJTT and demonstrate the potential in human surgery. This system offers a new path forward to achieving improved outcomes in Le Fort-based FJTT and can be modified to assist with a variety of other surgeries involving the head, neck, face, jaws and teeth.

Optimizing Hybrid Occlusion in Face-Jaw-Teeth Transplantation

“…The registration errors were 0.727 mm and 0.306 mm for the plastic skull model donor and recipient, respectively, and 1.22 mm and 0.745 mm for the human cadaver donor and recipient, respectively. 9 The face-jaw-teeth transplantation performed on the plastic skull retained the preoperative class I profile. The obtained human cadaver posttransplant molar relation (class I) matched the planned skeletal relation (class I), even though the donor and recipient originally exhibited class II and class I molar relations, respectively (Fig.…”

“…The total computer-assisted planning and execution setup preparation required approximately 11 minutes (Table 3). The learning curve for this setup is minimal; prior studies on plastic and animal models 8,9 helped to achieve this setup time. The registration errors were 0.727 mm and 0.306 mm for the plastic skull model donor and recipient, respectively, and 1.22 mm and 0.745 mm for the human cadaver donor and recipient, respectively.…”

“…8,9 Briefly, this technology provides surgeons various tools related to the planning and execution of face-jaw-teeth transplantation. Significant modules include biomechanical and geometric planning, patient-specific bone and soft-tissue cutting guides, navigation to confirm cutting guide and quantitative) of the repositioning of the donor fragment.…”

“…These trackable cutting guides were fabricated using additive manufacturing—also known as three-dimensional printing—with stereolithography. 8,9 In the cadaveric scenario, soft-tissue cutting guides were also fabricated to guide the incision path. After performing intraoperative registration (Fig.…”

“…8,9 The resulting system creates a patient-specific plan and uses trackable cutting guides (for both donor and recipient) to effectively perform face-jaw-teeth transplantation. Intraoperatively, the computer-assisted planning and execution workstation offers real-time position feedback of the donor fragment.…”